The present invention relates to a power module, particularly to a power module of motor drive control improving its heat radiation performance suitable for home electric appliances, industrial devices and automobiles.
In traditional power modules having switching elements and used in various field, for example, MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor) have been applied. The power module frequently has adopted a resin sealing structure to improve reliability of electric parts and productivity of modules. In such power modules of the resin seal structure, to improve heat radiating performance, a surface mounting the switching elements are covered with resin and a heat radiation layer of reverse side surface is exposed and makes surface contact to an external module mounting portion with grease or the like. Accordingly, a heat radiation path is insured to radiating heat generated inside of the switching elements to outside.
In the future, according to require a multi-function power module, high power and high mounting density, heat quantity of the power module is tendency to increase. With keeping reliability, by adopting such structure so as to keep heat radiation path, it is able to diffuse and radiate heat generated by the switching elements at the heat radiation layer and radiate heat efficiently to the module mounting portion with wide area.
For example, a resin sealed power module structure is disclosed in a patent document, Japanese laying open patent publication 2001-189325.